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Understanding the Units used in CENSUS® and QuantArray® Reports

Written by Microbial Insights | Feb 6, 2026 2:42:57 PM

CENSUS® qPCR and QuantArray® analyses can be performed on nearly any sample type, including water, solids like soil or corrosion product scrapings, Bio-Trap® samplers , and swabs of biofilms. The units the results are reported in depend on the sample matrix that was submitted for the analysis. For example, water samples will be reported as cells/mL, soil samples will have units of cells/g, and Bio-Traps® will be reported as cells/bead.

Comparing Results to Threshold Concentrations

Lu et al. (2006) proposes using a Dehalococcoides concentration of 1×104 cells/mL as a screening criterion to identify sites where biological reductive dechlorination is predicted to proceed at “generally useful” rates. Although there is not a direct conversion between cells/mL, cells/g, and cells/bead, in Microbial Insights’ experience, they typically fall within 1-2 orders of magnitude from each other. Dehalococcoides results of 1×104 cells/mL and 1×104 cells/bead are both likely to be sufficient concentrations for useful rates of reductive dechlorination.

Putting Microbiology in Context

The best way to understand if a concentration is high, medium, or low, is to access the Microbial Insights database and review the percentile rankings for each organism related to that particular sample matrix. With CENSUS® qPCR and QuantArray® results for more than 250,000 field samples from sites around the world, this database is the largest collection of field concentrations of key microorganisms and functional genes.

In practice, biodegradation depends not just on the presence but the actual concentrations of the contaminant degrading microorganisms. The percentile rankings retrieved from the Microbial Insights Database answer the question “Is that low, medium or high?” by comparing your results to those of the literally thousands of other environmental samples submitted to MI for analysis over the last 30+ years.

For more insights and information go to https://microbe.com/quantarray-mic/

Connect with us today: info@microbe.com or (865) 573-8188.